Marcel Minnaert studied biology at the University of Ghent in his native Belgium and physics at the University of Leiden in the Netherlands. After World War I he joined the solar physics group at the University of Utrecht in the Netherlands. From 1937 to 1963 he was director of the Utrecht Observatory. He and his students led in the development of detailed quantitative analysis of the solar spectrum, culminating in the publication of the famous “Utrecht Atlas” in 1940. Their development of the curve of growth method made it possible for astronomers to obtain precise information about stellar atmospheres. He investigated light scattering from the surface of the moon and participated in the naming of many lunar features. Imprisoned during World War II, he taught astronomy and physics to his fellow prisoners. After the war he was active in international organizations. A revered teacher, Minnaert published a collection of poems related to astronomy and popular books, including the classic Nature Of Light And Colour in the Open Air, as well as textbooks.